More specifically, the present invention relates to an overwrapping machine, for packets of cigarettes, of the type comprising a first feed line for feeding the packets of cigarettes successively along a first path; a second feed line for feeding sheets of transparent packing material successively along a second path, the first path intersecting the second path at a cross station to pair each packet with a respective sheet of packing material; and a guide, for guiding the packets, located upstream from the cross station and having an output end, for the packets, facing the cross station.
In known overwrapping machines of the type described above, the second feed line normally comprises an output portion defined by two conveyors, which are arranged side by side and a given distance apart through the cross station and along the second path. The two conveyors define a conveying surface for conveying the sheets of packing material through the cross station, and feed the sheets of packing material forward in steps, holding them by their longitudinal edges only, so that, at the cross station, a central portion of each sheet is positioned facing the output end of the packet guide. The two conveyors also define between them a passage through which the packets of cigarettes issuing from the guide are fed successively to engage and draw along the respective sheets of packing material.
Since the transparent material employed on overwrapping machines of the type described above is normally extremely thin and difficult to position, and given the tendency to locate the output end of the guide as close as possible to the conveying surface of the sheets of packing material to control the packets and pairing of the packets with the respective sheets of packing material as accurately as possible, the sheets of packing material engaging the cross station are subject to collision and tearing against the output end of the guide, thus resulting in jamming of the overwrapping machine.